It is known that, in a radiation field such as a boiling water type nuclear power plant, high temperature water in contact with a reactor structural material generates oxygen, hydrogen peroxide, or the like by radiolysis and the oxygen, the hydrogen peroxide, or the like causes a stress corrosion cracking to the reactor structural material.
Hydrogen injection technology of reducing oxygen or hydrogen peroxide in the reactor water by injecting hydrogen from a feed-water system has been developed for the countermeasure.
There exists, for example, noble metal injection technology in which hydrogen injection is carried out after a noble metal such as Pt or Rh is adhered to a surface of the reactor structural material to accelerate the reaction of the noble metal with hydrogen and increase an anode current and thereby corrosion potential is reduced as described in the following Patent Document 1.
A method for utilizing reaction of a photocatalyst using the photocatalyst as an anticorrosive agent has been attracting attention as a method for reducing the corrosion potential in recent years. The method is for reducing the corrosion potential by the action of electrons activated by photostimulated reaction caused by irradiating the photocatalyst arranged on a surface of a metal member with light having a wavelength of near-ultraviolet rays.
The photostimulated reaction efficiently proceeds by a noble metal being present near the photocatalyst. Therefore, it is disclosed in, for example, Patent Document 2 and Patent Document 3 that the corrosion potential while a reactor is in operation is reduced by allowing a high functional photocatalyst to which a photocatalyst or a noble metal is adhered to be adhered to the surface of the structural material in advance and causing the photostimulated reaction utilizing Cherenkov light to be generated in a reactor core.
Moreover, as a construction method for injecting a chemical into the reactor, a method for allowing a chemical to be adhered to the surface of the reactor structural material by injecting the chemical into the reactor during a shutdown period of the reactor or while the reactor is in operation and spreading the chemical on the surface of the reactor structural material is proposed in Patent Document 4 and Patent Document 5.
The method described in the above-described Patent Documents 4 and 5 is a method for injecting a solution, a dispersed particles, or the like into a reactor system and injecting only a chemical into high temperature water, in particular, into high temperature water in a reactor.